电磁层析成像系统的软硬件设计

发布时间：2018-04-15 22:30

本文选题：电磁层析成像 + 线圈传感器　；参考：《辽宁大学》2015年硕士论文

【摘要】：电磁层析成像(Electromagnetic Tomography,EMT)技术是近几年来发展起来的一种新型无损的过程检测技术。它将麦克斯韦电磁感应理论与“由投影重建图像”的理论相结合。而且由于其电磁传感器具有可远程检测,非接触和无危害等检测优点,因此可广泛应用于工业过程中化工分离、环境监测、地质勘探及医学研究等领域。本文在查阅了大量国内外文献的基础上,分析了电磁层析成像系统的国内外研究现状,详细阐述了电磁层析成像系统基本原理;然后对电磁层析成像系统进行了设计,该系统主要包括为硬件电路部分及软件部分。硬件电路包括传感器阵列、激励源信号电路、多路开关电路、采集放大电路及相敏检波电路,软件部分主要利用C语言、matlab语言和labview软件进行设计。主要完成了以下几点工作:1、设计了电磁层析成像的系统电路。首先为了获得高精度,低失真的正弦波信号,采用了DDS芯片AD9850作为系统的激励源;然后采用舌簧继电器G6K-2P-Y作为多路开关电路的开关部分,实现对输入线圈传感器的电信号进行绝对物理隔离和物理连接控制;然后采用具有优异信噪比的精密程控增益放大器AD603作为采集放大电路的前置放大器,将淹没在噪声中的微弱电信号提取出来;最后采用乘法器AD534对检测信号进行硬件乘法解调,获得比数字乘法解调更为精确的电压信号。2、实现了对系统软件的编程。首先利用C语言对STM32核心板编程实现了对多路开关进行逻辑控制,并对28组检测电压信号进行数据采集和处理;利用matlab语言进行图像重建程序设计;然后在labview界面中使用VISA模块和matlab script节点实现对数据的读取与界面编程。3、搭建了电磁层析成像系统实验平台,并进行了仿真实验,实验结果表明在本系统硬件电路平台和软件编程基础上实现了微弱检测信号的采集与放大、多路开关控制、数据传输与处理、重建图像显示。实验结果达到了预期要求。
[Abstract]:Electromagnetic Tomography (EMT) is a new nondestructive process detection technique developed in recent years.It combines Maxwell's electromagnetic induction theory with the "image reconstruction from projection" theory.Because its electromagnetic sensor has the advantages of remote detection, non-contact and non-hazard detection, it can be widely used in the industrial process of chemical separation, environmental monitoring, geological exploration and medical research and other fields.On the basis of consulting a large number of literatures at home and abroad, this paper analyzes the current research situation of electromagnetic tomography system at home and abroad, expounds the basic principle of electromagnetic tomography system in detail, and then designs the electromagnetic tomography system.The system mainly includes hardware circuit and software.The hardware circuit includes sensor array, excitation source signal circuit, multiplex switch circuit, acquisition amplifier circuit and phase sensitive detection circuit. The software is mainly designed with C language and labview software.The main work is as follows: 1. The system circuit of electromagnetic tomography is designed.In order to obtain high precision and low distortion sinusoidal signal, the DDS chip AD9850 is used as the excitation source of the system, and the tongue spring relay G6K-2P-Y is used as the switch part of the multiplex switch circuit.To realize the absolute physical isolation and physical connection control of the electrical signal of the input coil sensor, and then use the precision program-controlled gain amplifier (AD603) with excellent SNR as the preamplifier of the acquisition amplifier circuit.The weak electrical signal submerged in noise is extracted, and the detection signal is demodulated by hardware multiplication using multiplier AD534. The voltage signal .2is more accurate than digital multiplication demodulation, and the software of the system is programmed.Firstly, the STM32 core board is programmed with C language to realize the logic control of the multiplex switch, and 28 groups of detecting voltage signals are collected and processed, and the image reconstruction program is designed by using the matlab language.Then the data reading and interface programming. 3 are realized by using VISA module and matlab script node in the labview interface. The experiment platform of electromagnetic tomography system is built, and the simulation experiment is carried out.The experimental results show that the acquisition and amplification of weak detection signal, the control of multi-switch, the data transmission and processing, and the reconstruction of image display are realized on the basis of the hardware circuit platform and software programming of the system.The experimental results meet the expected requirements.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB302.5

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